Former art school student turned drop-out. Has an affinity for art and seems to be able to tell you a lot about an artist, architect, designer, etc. based on their completed work. She also has issues with color, being unable/unwilling to interact with certain colors. (Example: Stabbed her art-school roommate after the roomie painted the door yellow and Hannah became essentially "trapped" and had to exit the window.)
A man in his 40s, former Iraq war veteran, mentally screwed up by the experience. He doesn't have any substance abuse issues, but does have mental problems. Lack of treatment and medicine has allowed these issues to progress fully. He tends to be a bully and keep the newly-homeless in line, or at least show them their place. There is a definite pecking order amongst the homeless population. He may not be the top king-bee, but he's one of them. He treats his few friends reasonably well (meaning he doesn't yell at them, insult them, or bully them), but does get forceful on most others on an as-needed basis (use your imagination there). He has had numerous run-ins with the law (who all know him by first name) including a couple of health-related arrests (at the hospital he actually got treatment for a short time), but hasn't committed any hard-core crimes (such as thefts or assaults - at least not when police are around). He has been living in the streets for the past 3 years, and is a regular fixture in the population. He travels light, eats at the soup kitchens (when he's not in a freaky mental state), occasionally lands shelter and/or shower, and has a defined territory.
Young Medical doctor got into deep debt. Started using drugs to work longer hours at the hospital. He killed a few patients by accident due to the drugs he was using. He got fired, became a drug addict, lost his family, house, friends, everything. He now lives on the street, helping when he can and if he's not too high. He thinks he can hear and see dead people; specifically the ghosts of those he killed. (They are haunting him.)
Michele's character's name tends to change on a regular basis, but always to something where the first and last names have the same starting letter (AA, BB, etc.)
African American former scientist, confined to a wheelchair. He seems to be the group's conspiracy theorist.